Ascorbic Acid and selenium has a potential use in the prevention of cancer. The role of antioxidant enzymes against cancer is to prevent oxidative damage. The aim of the study was to investigate the effect of Ascorbic Acid and selenium on antioxidant enzyme activities in HepG2 cell line. In this study, the effects of Org Se (234 µM), SeO2 (100 µM), Ascorbic Acid (31,3 mM) and Ascorbic Acid (0,313 mM) on antioxidant enzyme activities in HepG2 cell line were studied. GPx, CAT and SOD activities were measured spectrophotometrically. There was a significant increase in the activity of GPx in HepG2 cells treated with Org Se (234 µM), SeO2 (100 µM), Ascorbic Acid (31,3 mM) and Ascorbic Acid (0,313 mM), however the activity of CAT was found significantly decreased in Org Se (234 µM), SeO2 (100 µM), Ascorbic Acid (31,3 mM) treated HepG2 cells. The SOD levels of HepG2 cells treated with Ascorbic Acid (31,3 mM) and AA (0,313 mM) were found higher than the control cells. The results of the present study indicated that the antioxidant enzyme activities changed depending on Org Se, SeO2 application and CAT activities changed depending on Ascorbic Acid doses.